This protocol is concerned with the allergic reaction of some individuals to the sting of the imported fire ant (Solenopsis invicta). With recent evidence of a lack of efficacy of whole body extract (WBE) immunotherapy for individuals allergic to other members of the order Hymenoptera, and the advent of honeybee, Vespid, and Polistes venom immunotherapy, the role of fire ant WBE immunotherapy must be closely scrutinized. The role of the proposed studies in this protocol is to evaluate the efficacy of fire ant WBE and fire ant venom as treatment materials for patients with fire ant venom hypersensitivity. In this regard, we plan to (1) purify and characterize fire ant venom proteins; (2) investigate the importance of venom, venom components, and venom alkaloids as allergens in fire ant allergic individuals; (3) develop a radioimmunoprecipitation assay to measure the levels of IgG blocking antibody to assess the effectiveness of treatment; (4) finally, we would like to compare the cross-reactivity of fire ant venom proteins with proteins in other Hymenoptera venoms.